/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.rest.handler.util;

import org.apache.flink.runtime.executiongraph.AccessExecution;
import org.apache.flink.runtime.executiongraph.ExecutionGraph;
import org.apache.flink.runtime.executiongraph.IOMetrics;
import org.apache.flink.runtime.metrics.MetricNames;
import org.apache.flink.runtime.rest.handler.job.JobVertexDetailsHandler;
import org.apache.flink.runtime.rest.handler.legacy.metrics.MetricFetcher;
import org.apache.flink.runtime.rest.handler.legacy.metrics.MetricStore;

import javax.annotation.Nullable;

/**
 * This class is a mutable version of the {@link IOMetrics} class that allows adding up IO-related
 * metrics.
 *
 * <p>For finished jobs these metrics are stored in the {@link ExecutionGraph} as another {@link
 * IOMetrics}. For running jobs these metrics are retrieved using the {@link MetricFetcher}.
 *
 * <p>This class provides a common interface to handle both cases, reducing complexity in various
 * handlers (like the {@link JobVertexDetailsHandler}).
 */
public class MutableIOMetrics extends IOMetrics {

    private static final long serialVersionUID = -5460777634971381737L;
    private boolean numBytesInComplete = true;
    private boolean numBytesOutComplete = true;
    private boolean numRecordsInComplete = true;
    private boolean numRecordsOutComplete = true;

    public MutableIOMetrics() {
        super(0, 0, 0, 0);
    }

    public boolean isNumBytesInComplete() {
        return numBytesInComplete;
    }

    public boolean isNumBytesOutComplete() {
        return numBytesOutComplete;
    }

    public boolean isNumRecordsInComplete() {
        return numRecordsInComplete;
    }

    public boolean isNumRecordsOutComplete() {
        return numRecordsOutComplete;
    }

    /**
     * Adds the IO metrics for the given attempt to this object. If the {@link AccessExecution} is
     * in a terminal state the contained {@link IOMetrics} object is added. Otherwise the given
     * {@link MetricFetcher} is used to retrieve the required metrics.
     *
     * @param attempt Attempt whose IO metrics should be added
     * @param fetcher MetricFetcher to retrieve metrics for running jobs
     * @param jobID JobID to which the attempt belongs
     * @param taskID TaskID to which the attempt belongs
     */
    public void addIOMetrics(
            AccessExecution attempt, @Nullable MetricFetcher fetcher, String jobID, String taskID) {
        if (attempt.getState().isTerminal()) {
            IOMetrics ioMetrics = attempt.getIOMetrics();
            if (ioMetrics != null) { // execAttempt is already finished, use final metrics stored in
                // ExecutionGraph
                this.numBytesIn += ioMetrics.getNumBytesIn();
                this.numBytesOut += ioMetrics.getNumBytesOut();
                this.numRecordsIn += ioMetrics.getNumRecordsIn();
                this.numRecordsOut += ioMetrics.getNumRecordsOut();
            }
        } else { // execAttempt is still running, use MetricQueryService instead
            if (fetcher != null) {
                fetcher.update();
                MetricStore.ComponentMetricStore metrics =
                        fetcher.getMetricStore()
                                .getSubtaskMetricStore(
                                        jobID, taskID, attempt.getParallelSubtaskIndex());
                if (metrics != null) {
                    /**
                     * We want to keep track of missing metrics to be able to make a difference
                     * between 0 as a value and a missing value. In case a metric is missing for a
                     * parallel instance of a task, we set the complete flag as false.
                     */
                    if (metrics.getMetric(MetricNames.IO_NUM_BYTES_IN) == null) {
                        this.numBytesInComplete = false;
                    } else {
                        this.numBytesIn +=
                                Long.valueOf(metrics.getMetric(MetricNames.IO_NUM_BYTES_IN));
                    }

                    if (metrics.getMetric(MetricNames.IO_NUM_BYTES_OUT) == null) {
                        this.numBytesOutComplete = false;
                    } else {
                        this.numBytesOut +=
                                Long.valueOf(metrics.getMetric(MetricNames.IO_NUM_BYTES_OUT));
                    }

                    if (metrics.getMetric(MetricNames.IO_NUM_RECORDS_IN) == null) {
                        this.numRecordsInComplete = false;
                    } else {
                        this.numRecordsIn +=
                                Long.valueOf(metrics.getMetric(MetricNames.IO_NUM_RECORDS_IN));
                    }

                    if (metrics.getMetric(MetricNames.IO_NUM_RECORDS_OUT) == null) {
                        this.numRecordsOutComplete = false;
                    } else {
                        this.numRecordsOut +=
                                Long.valueOf(metrics.getMetric(MetricNames.IO_NUM_RECORDS_OUT));
                    }
                } else {
                    this.numBytesInComplete = false;
                    this.numBytesOutComplete = false;
                    this.numRecordsInComplete = false;
                    this.numRecordsOutComplete = false;
                }
            }
        }
    }
}
